The present invention concerns an improved bearing-and-brake-member assembly for a motor vehicle, provided with an intermediate connection element between the bearing and the brake member, and more particularly it concerns the mounting of a brake member such as a disc or drum on a rotating ring of a bearing of a driving wheel or a free wheel of a motor vehicle.
It is known that disc or drum brake members for motor vehicles are mounted directly on the rotating ring of the wheel bearing, which is provided with a radial flange to which the disc or drum is connected; in particular, the disc, preferably associated with a driving wheel, is mounted in contact with a flange of the inner ring of the bearing, and fixed to the wheel by means of bolts screwed to the flange, or nuts screwed to captive bolts fixed to the flange; similarly, the drum, usually associated with a free wheel, is connected to the flange of a rotating outer ring of the bearing, fixed to the wheel by bolts screwed to the flange, or nuts screwed to captive bolts fixed to the flange.
Due to working tolerances in the manufacture of the wheel, the flange and the brake member, it is not possible to avoid irregularities in the flatness of the facing surfaces of the parts to be joined together. Such flatness errors give rise on tightening the bolts to deformations in the bearing tracks and the active surfaces of the brake members (on which the brake pads or shoes act) in the form of ovalization, undulations and the formation of lobes. These disadvantages give rise to vibrations, braking noise and irregular wear of the active surfaces of the brake members, in addition reducing the resistance of the bearing to fatigue.
A known solution to these disadvantages is to use components (wheels, braking members, bearing flanges) manufactured to high precision or, alternatively, to use a bearing having a flange of great thickness and rigidity so as to resist the deformations caused by tightening the wheel-fixing screws.
However, these solutions are disadvantageous in terms of their effect on the cost and weight of the assembly.